Add support for neato engine no-op command-line flag

[clayms]

Is it possible to use the neato engine no-op command-line flag (-n CLI flag) to add to an existing graph without altering the current node locations?

See "-n[num]" in https://graphviz.gitlab.io/doc/info/command.html

Neato Layout Manual.

[xflr6]

Thanks. Marking this as enhancement.

Would you like to give it a try?

Probably similar to the formatter argument:

graphviz/graphviz/files.py

Lines 202 to 205 in a542d04

	def render(self, filename=None, directory=None, view=False, cleanup=False,
	format=None, renderer=None, formatter=None,
	quiet=False, quiet_view=False):
	"""Save the source to file and render with the Graphviz engine.

graphviz/graphviz/files.py

Lines 143 to 144 in a542d04

	def pipe(self, format=None, renderer=None, formatter=None, quiet=False):
	"""Return the source piped through the Graphviz layout command.

[xflr6]

See https://graphviz.gitlab.io/doc/info/command.html#-n

[neogeno]

+1 - can someone give me some advice to add a PR myself so that I can pass -n2 to the neato engine?

[xflr6]

The code moved around a bit since then (better structure).

We need a new argument similar to the formatter argument:

graphviz/graphviz/backend/dot_command.py

Lines 15 to 19 in ee3ae10

	def command(engine: str, format_: str, *,
	renderer: typing.Optional[str] = None,
	formatter: typing.Optional[str] = None
	) -> typing.List[typing.Union[os.PathLike, str]]:
	"""Return ``subprocess.Popen`` argument list for rendering.

graphviz/graphviz/backend/rendering.py

Lines 197 to 206 in ee3ae10

	def render(engine: str,
	format: typing.Optional[str] = None,
	filepath: typing.Union[os.PathLike, str, None] = None,
	renderer: typing.Optional[str] = None,
	formatter: typing.Optional[str] = None,
	quiet: bool = False, *,
	outfile: typing.Union[os.PathLike, str, None] = None,
	raise_if_result_exists: bool = False,
	overwrite_filepath: bool = False) -> str:
	r"""Render file with ``engine`` into ``format`` and return result filename.

Also the overload annoations above.

graphviz/graphviz/backend/piping.py

Lines 15 to 19 in ee3ae10

	def pipe(engine: str, format: str, data: bytes,
	renderer: typing.Optional[str] = None,
	formatter: typing.Optional[str] = None,
	quiet: bool = False) -> bytes:
	"""Return ``data`` (``bytes``) piped through ``engine`` into ``format`` as ``bytes``.

Also the other pipe functions above.

graphviz/graphviz/rendering.py

Lines 22 to 36 in ee3ae10

	def render(self,
	filename: typing.Union[os.PathLike, str, None] = None,
	directory: typing.Union[os.PathLike, str, None] = None,
	view: bool = False,
	cleanup: bool = False,
	format: typing.Optional[str] = None,
	renderer: typing.Optional[str] = None,
	formatter: typing.Optional[str] = None,
	quiet: bool = False,
	quiet_view: bool = False, *,
	outfile: typing.Union[os.PathLike, str, None] = None,
	engine: typing.Optional[str] = None,
	raise_if_result_exists: bool = False,
	overwrite_source: bool = False) -> str:
	r"""Save the source to file and render with the Graphviz engine.

graphviz/graphviz/piping.py

Lines 52 to 59 in ee3ae10

	def pipe(self,
	format: typing.Optional[str] = None,
	renderer: typing.Optional[str] = None,
	formatter: typing.Optional[str] = None,
	quiet: bool = False, *,
	engine: typing.Optional[str] = None,
	encoding: typing.Optional[str] = None) -> typing.Union[bytes, str]:
	"""Return the source piped through the Graphviz layout command.

Also overload and the private implementations above.

Not sure about the naming, maybe neato_no_op, or neato_no_op_num (type: Union[bool, int], maybe Optional[int] or Union[bool, int, None])?

Needs test coverage naturally.

[xflr6]

Work in progress in 4ac5a25.

[xflr6]

Added in version 0.20, closing.